Preheat your oven to 375°F (190°C) and prepare a mini muffin tin by lining it with paper liners or greasing it lightly.

Gently unroll the thawed puff pastry on a lightly floured surface, then cut it into 24 squares, each approximately 2x2 inches.

Press one pastry square into each well of the prepared muffin tin, allowing the corners to extend slightly.

Place a small cube of brie in the center of each pastry square, topping it with about 1/2 teaspoon of cranberry sauce and optionally a few chopped pecans.

Carefully fold the pastry corners over the filling, pinching them together gently to partially encase the ingredients.

Whisk the egg with a tablespoon of water to create an egg wash, then lightly brush it over the tops of the pastries.

Bake for 12-15 minutes, or until the pastry is golden brown and puffed, and the brie is melted and bubbly.

Remove the bites from the muffin tin and cool them slightly on a wire rack before serving, garnishing with fresh rosemary or thyme if desired.